Superchat Backend Challenge

This is a simple API replicating the core functionality of a communications platform. It includes the following core functionality:

Create contacts given their name and email
List all contacts
Send a message to a contact
List all previous conversations
Receive messages from an external service via a webhook
Automatically substitute placeholder text in messages

Tech Stack

Kotlin
Ktor (web framework)
H2 (in-memory database)
Exposed (type-safe SQL framework)

Endpoints

Contacts

POST /contacts - Create a new contact

Request body:

{
  "name": "Yanchen Ma",
  "email": "yanchen@example.com"
}

Response: 201 CREATED

{
  "name": "Yanchen Ma",
  "email": "yanchen@example.com",
  "created": 1611806692403
}

GET /contacts - List all contacts

Request body: None
Response: 200 OK

[
  {
    "name": "Yanchen Ma",
    "email": "yanchen@example.com",
    "created": 1611806692403
  },
  ...
]

GET /contacts/{email} - Get contact with given email

Request body: None
Response: 200 OK / 404 NOT FOUND

{
  "name": "Yanchen Ma",
  "email": "yanchen@example.com",
  "created": 1611806692403
}

DELETE /contacts/{email} - Delete contact with given email

Request body: None
Response: 200 OK / 404 NOT FOUND

Messages

POST /messages - Send message to contact

Request body:
- Wrap any placeholders in ${ }.
- Currently supported placeholders are name, email, and btc

{
  "contact": "yanchen@example.com",
  "body": "Hi ${name}, the current price of bitcoin is ${btc}."
}

Response: 201 CREATED

{
  "id": 1,
  "contact": "yanchen@example.com",
  "type": "SENT",
  "body": "Hi Yanchen Ma, the current price of bitcoin is 31455.75.",
  "sent": 1611807391337
}

POST /receive - Receive message from external service

Request body:
- If given email already exists in system, use existing contact
- Otherwise, create a new contact with the given information
- Placeholders are not supported

{
  "email": "other@example.com",
  "name": "John Smith",
  "message": "Hello there"
}

Resposne: 200 OK

{
  "name": "John Smith",
  "email": "other@example.com",
  "message": "Hello there"
}

GET /messages - List all past conversations

Request body: None
Response: 200 OK

[
  {
    "id": 2,
    "contact": "other@example.com",
    "type": "RECEIVED",
    "body": "Hello there",
    "sent": 1611797303604
  },
  {
    "id": 1,
    "contact": "yanchen@example.com",
    "type": "SENT",
    "body": "Hi Yanchen Ma, the current price of bitcoin is 31455.75.",
    "sent": 1611797298836
  }
]

GET /messages/{email} - Get all messages with a particular contact

Request body: None
Response: 200 OK

[
  {
    "id": 1,
    "contact": "yanchen@example.com",
    "type": "SENT",
    "body": "Hi Yanchen Ma, the current price of bitcoin is 31455.75.",
    "sent": 1611797298836
  }
]

GET /message/{id} - Get message by ID

Request body: None
Response: 200 OK / 404 NOT FOUND

{
  "id": 2,
  "contact": "other@example.com",
  "type": "RECEIVED",
  "body": "Hello there",
  "sent": 1611797303604
}

Running Locally

To run the API locally, simply clone the repo and run:

docker-compose up